Rapid turnover of the intestinal epithelium is a critical strategy to balance the uptake of nutrients and defend against environmental insults, whereas inappropriate death promotes the spread of inflammation. PPARα is highly expressed in the small intestine and regulates the absorption of dietary lipids. However, as a key mediator of inflammation, the impact of intestinal PPARα signaling on cell death pathways is unknown. Here, we show that Pparα deficiency of intestinal epithelium up-regulates necroptosis signals, disrupts the gut vascular barrier, and promotes LPS translocation into the liver. Intestinal Pparα deficiency drives age-related hepatic steatosis and aggravates hepatic fibrosis induced by a high-fat plus high-sucrose diet (HFHS). PPARα levels correlate with TRIM38 and MLKL in the human ileum. Inhibition of PPARα up-regulates necroptosis signals in the intestinal organoids triggered by TNF-α and LPS stimuli via TRIM38/TRIF and CREB3L3/MLKL pathways. Butyric acid ameliorates hepatic steatosis induced by intestinal Pparα deficiency through the inhibition of necroptosis. Our data suggest that intestinal PPARα is essential for the maintenance of microenvironmental homeostasis and the spread of inflammation via the gut-liver axis.

OBJECTIVETo explore the effects of different concentrations of putrescine on the proliferation, migration and apoptosis of human skin fibroblasts (HSF).

METHODSHSF cultured in the presence of 0.5, 1.0, 5.0, 10, 50, 100, 500, and 1000 µg/ putrescine for 24 h were examined for the changes in the cell proliferation, migration, and apoptosis using MTS assay, Transwell migration assay, and flow cytometry, respectively.

RESULTSCompared with the control cells, HSF cultured with 0.5, 1.0, 5.0, and 10 µg/ putrescine showed significantly increased cell proliferation (P<0.01), and the effect was the most obvious with 1 µg/ putrescine, whereas 500 and 1000 µg/ putrescine significantly reduced the cell proliferation (P<0.01); 50 and 100 µg/ did not obviously affect the cell proliferation (P>0.05). Putrescine at 1 µg/ most significantly enhanced the cell migration (P<0.01), while at higher doses (50, 100, 500, and 1000 µg/) putrescine significantly suppressed the cell migration (P<0.05); 0.5, 5.0, and 10 µg/ putrescine produced no obvious effects on the cell migration (P>0.05). HSF treated with 0.5, 1.0, 5.0, and 10 µg/ putrescine obvious lowered the cell apoptosis rate compared with the control group (P<0.01), and the cell apoptosis rate was the lowest in cells treated with 1 µg/ putrescine; but at the concentrations of 100, 500, and 1000 µg/, putrescine significantly increased the cell apoptosis rate (P<0.01), while 50 µg/ml putrescine produced no obvious effect on cell apoptosis (P>0.05).

CONCLUSIONLow concentrations of putrescine can obviously enhance the proliferation ability and maintain normal migration ability of HSF in vitro, but at high concentrations, putrescine can obviously inhibit the cell migration and proliferation and induce cells apoptosis, suggesting the different roles of different concentrations of putrescine in wound healing.

Apoptosis ; drug effects ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Fibroblasts ; cytology ; drug effects ; Flow Cytometry ; Humans ; Putrescine ; administration & dosage ; pharmacology ; Skin ; cytology ; Wound Healing

OBJECTIVETo explore the effects of different concentrations of putrescine on proliferation, migration, and apoptosis of human umbilical vein endothelial cells (HUVECs).

METHODSHUVECs were routinely cultured in vitro. The 3rd to the 5th passage of HUVECs were used in the following experiments. (1) Cells were divided into 500, 1 000, and 5 000 µg/mL putrescine groups according to the random number table (the same grouping method was used for following grouping), with 3 wells in each group, which were respectively cultured with complete culture solution containing putrescine in the corresponding concentration for 24 h. Morphology of cells was observed by inverted optical microscope. (2) Cells were divided into 0.5, 1.0, 5.0, 10.0, 50.0, 100.0, 500.0, 1 000.0 µg/mL putrescine groups, and control group, with 4 wells in each group. Cells in the putrescine groups were respectively cultured with complete culture solution containing putrescine in the corresponding concentration for 24 h, and cells in control group were cultured with complete culture solution with no additional putrescine for 24 h. Cell proliferation activity (denoted as absorption value) was measured by colorimetry. (3) Cells were divided (with one well in each group) and cultured as in experiment (2), and the migration ability was detected by transwell migration assay. (4) Cells were divided (with one flask in each group) and cultured as in experiment (2), and the cell apoptosis rate was determined by flow cytometer. Data were processed with one-way analysis of variance, Kruskal-Wallis test, and Dunnett test.

RESULTS(1) After 24-h culture, cell attachment was good in 500 µg/mL putrescine group, and no obvious change in the shape was observed; cell attachment was less in 1 000 µg/mL putrescine group and the cells were small and rounded; cells in 5 000 µg/mL putrescine group were in fragmentation without attachment. (2) The absorption values of cells in 0.5, 1.0, 5.0, 10.0, 50.0, 100.0, 500.0, 1 000.0 µg/mL putrescine groups, and control group were respectively 0.588 ± 0.055, 0.857 ± 0.031, 0.707 ± 0.031, 0.662 ± 0.023, 0.450 ± 0.019, 0.415 ± 0.014, 0.359 ± 0.020, 0.204 ± 0.030, and 0.447 ± 0.021, with statistically significant differences among them (χ(2) = 6.86, P = 0.009). The cell proliferation activity in 0.5, 1.0, 5.0, and 10.0 µg/mL putrescine groups was higher than that in control group (P < 0.05 or P < 0.01). The cell proliferation activity in 500.0 and 1 000.0 µg/mL putrescine groups was lower than that in control group (with P values below 0.01). The cell proliferation activity in 50.0 and 100.0 µg/mL putrescine groups was close to that in control group (with P values above 0.05). (3) There were statistically significant differences in the numbers of migrated cells between the putrescine groups and control group (F = 138.662, P < 0.001). The number of migrated cells was more in 1.0, 5.0, and 10.0 µg/mL putrescine groups than in control group (with P value below 0.01). The number of migrated cells was less in 500.0 and 1 000.0 µg/mL putrescine groups than in control group (with P value below 0.01). The number of migrated cells in 0.5, 50.0, and 100.0 µg/mL putrescine groups was close to that in control group (with P values above 0.05). (4) There were statistically significant differences in the apoptosis rate between the putrescine groups and control group (χ(2)=3.971, P=0.046). The cell apoptosis rate was lower in 0.5, 1.0, 5.0, and 10.0 µg/mL putrescine groups than in control group (with P values below 0.05). The cell apoptosis rate was higher in 500.0 and 1 000.0 µg/mL putrescine groups than in control group (with P values below 0.01). The cell apoptosis rates in 50.0 and 100.0 µg/mL putrescine groups were close to the cell apoptosis rate in control group (with P values above 0.05).

CONCLUSIONSLow concentration of putrescine can remarkably enhance the ability of proliferation and migration of HUVECs, while a high concentration of putrescine can obviously inhibit HUVECs proliferation and migration, and it induces apoptosis.

Apoptosis ; drug effects ; Biological Products ; Cell Line ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Flow Cytometry ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; Humans ; Putrescine ; administration & dosage ; adverse effects ; pharmacology ; physiology ; Skin ; cytology ; Wound Healing

Objective To explore the effects of different concentrations of putrescine on the proliferation, migration and apoptosis of human skin fibroblasts (HSF). Methods HSF cultured in the presence of 0.5, 1.0, 5.0, 10, 50, 100, 500, and 1000μg/ml putrescine for 24 h were examined for the changes in the cell proliferation, migration, and apoptosis using MTS assay, Transwell migration assay, and flow cytometry, respectively. Results Compared with the control cells, HSF cultured with 0.5, 1.0, 5.0, and 10μg/ml putrescine showed significantly increased cell proliferation (P<0.01), and the effect was the most obvious with 1 μg/ml putrescine, whereas 500 and 1000 μg/ml putrescine significantly reduced the cell proliferation (P<0.01); 50 and 100 μg/ml did not obviously affect the cell proliferation (P>0.05). Putrescine at 1 μg/ml most significantly enhanced the cell migration (P<0.01), while at higher doses (50, 100, 500, and 1000μg/ml) putrescine significantly suppressed the cell migration (P<0.05);0.5, 5.0, and 10μg/ml putrescine produced no obvious effects on the cell migration (P>0.05). HSF treated with 0.5, 1.0, 5.0, and 10 μg/ml putrescine obvious lowered the cell apoptosis rate compared with the control group (P<0.01), and the cell apoptosis rate was the lowest in cells treated with 1μg/ml putrescine;but at the concentrations of 100, 500, and 1000μg/ml, putrescine significantly increased the cell apoptosis rate (P<0.01), while 50μg/ml putrescine produced no obvious effect on cell apoptosis (P>0.05). Conclusion Low concentrations of putrescine can obviously enhance the proliferation ability and maintain normal migration ability of HSF in vitro, but at high concentrations, putrescine can obviously inhibit the cell migration and proliferation and induce cells apoptosis, suggesting the different roles of different concentrations of putrescine in wound healing.

Objective To explore the effects of different concentrations of putrescine on the proliferation, migration and apoptosis of human skin fibroblasts (HSF). Methods HSF cultured in the presence of 0.5, 1.0, 5.0, 10, 50, 100, 500, and 1000μg/ml putrescine for 24 h were examined for the changes in the cell proliferation, migration, and apoptosis using MTS assay, Transwell migration assay, and flow cytometry, respectively. Results Compared with the control cells, HSF cultured with 0.5, 1.0, 5.0, and 10μg/ml putrescine showed significantly increased cell proliferation (P<0.01), and the effect was the most obvious with 1 μg/ml putrescine, whereas 500 and 1000 μg/ml putrescine significantly reduced the cell proliferation (P<0.01); 50 and 100 μg/ml did not obviously affect the cell proliferation (P>0.05). Putrescine at 1 μg/ml most significantly enhanced the cell migration (P<0.01), while at higher doses (50, 100, 500, and 1000μg/ml) putrescine significantly suppressed the cell migration (P<0.05);0.5, 5.0, and 10μg/ml putrescine produced no obvious effects on the cell migration (P>0.05). HSF treated with 0.5, 1.0, 5.0, and 10 μg/ml putrescine obvious lowered the cell apoptosis rate compared with the control group (P<0.01), and the cell apoptosis rate was the lowest in cells treated with 1μg/ml putrescine;but at the concentrations of 100, 500, and 1000μg/ml, putrescine significantly increased the cell apoptosis rate (P<0.01), while 50μg/ml putrescine produced no obvious effect on cell apoptosis (P>0.05). Conclusion Low concentrations of putrescine can obviously enhance the proliferation ability and maintain normal migration ability of HSF in vitro, but at high concentrations, putrescine can obviously inhibit the cell migration and proliferation and induce cells apoptosis, suggesting the different roles of different concentrations of putrescine in wound healing.

OBJECTIVETo explore the influence of exogenous putrescine on the function of liver and apoptosis of liver cells in rats.

METHODSNinety healthy clean SD rats were divided into control group (C, n = 10, intraperitoneally injected with 2 mL normal saline), low dosage putrescine group (LP, n = 40), and high dosage putrescine group (HP, n = 40) according to the random number table. Rats in the latter two groups were intraperitoneally injected with approximately 2 mL putrescine (2.5 or 5.0 g/L) with the dosage of 25 or 50 µg/g. Ten rats from group C at post injection hour (PIH) 24 and 10 rats from each of the latter two groups at PIH 24, 48, 72, 96 were sacrificed. Heart blood was obtained for determination of serum contents of ALT and AST. Liver was harvested for gross observation and histomorphological observation with HE staining. Apoptosis was shown with in situ end labeling, and apoptosis index (AI) was calculated. Data among the three groups and those at different time points within one group were processed with one-way analysis of variance or Welch test; LSD or Dunnett's T3 test was used for paired comparison; factorial design analysis of variance of two factors was applied for data between group LP and group HP.

RESULTS(1) No obvious abnormality was observed at gross observation of liver of rats in each group. Liver tissue of rats in group C was normal. Light edema was observed occasionally in liver of rats in groups LP and HP, but necrotic cells were not seen. (2) Content of ALT at PIH 24, 48, 96 and content of AST at PIH 72 and 96 in group LP were respectively (38 ± 10), (45 ± 6), (34 ± 4), (207 ± 18), (196 ± 19) U/L, and content of ALT at PIH 72 and 96 and content of AST at PIH 24, 72, 96 in group HP were respectively (38 ± 6), (48 ± 5), (213 ± 43), (209 ± 40), (230 ± 29) U/L. They were significantly higher than those of rats in group C [(29 ± 5), (163 ± 42) U/L, with P values all below 0.01]. There were statistically significant differences between group LP and group HP in the content of ALT at PIH 48, 72, 96 and content of AST at PIH 96 (with P values all below 0.05). Compared with that at PIH 24 of each group, content of ALT of rats in group LP at PIH 48 and that of rats in group HP at PIH 96, as well as content of AST of rats in group LP at PIH 48, 72, 96 and that of rats in group HP at PIH 48 were significantly increased or decreased (with P values all below 0.05). Factorial analysis showed that the differences due to different concentration of putrescine on content of AST were statistically significant (F = 12.21, P = 0.001), but not on content of ALT (F = 0.01, P = 0.974) between group LP and group HP. (3) AI values of rats in group LP at PIH 24, 48, 72 were respectively (5.69 ± 0.38)%, (13.80 ± 1.66)%, (11.56 ± 1.74)%, and AI values of rats in group HP at PIH 72 and 96 were respectively (10.29 ± 1.43)%, (15.29 ± 1.41)%. They were all obviously higher than AI value of control group at PIH 24 [(3.50 ± 0.30)%, with P values all below 0.01]. There were statistically significant differences between group LP and group HP in AI value at PIH 24, 48, 96 (with P values all below 0.05). Compared with that at PIH 24 of each group, AI value of rats in groups LP and HP at PIH 48, 72, 96 were significantly increased or decreased (with P values all below 0.05). Factorial analysis showed that the differences in the influence of concentration of putrescine and stimulation time on AI value were statistically significant (with F values respectively 22.95 and 130.44, P values all below 0.01).

CONCLUSIONSIntraperitoneal injection of exogenous putrescine in the dosage of 25 or 50 µg/g could lead to certain degree of functional damage of liver and apoptosis of liver cells of rat. The higher the dosage and the longer the stimulation time, the more obvious the damage and apoptosis would be.

Alanine Transaminase ; blood ; Animals ; Apoptosis ; drug effects ; Hepatocytes ; cytology ; drug effects ; Liver ; cytology ; pathology ; Putrescine ; toxicity ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the effect of exogenous putrescine on renal function and cell apoptosis in rats.

METHODSNinety SD rats were randomized into control group (n=10), high-dose putrescine group (P1 group, n=40), and low-dose putrescine group (P2 group, n=40) with intraperitoneal injections of 2 ml of normal saline, 50 µg/g putrescine, and 25 µg/g putrescine, respectively. At 24, 48, 72 and 96 h after the injections, 10 rats from each group were sacrificed to examine serum Cr and BUN levels, histological changes in the kidneys, and renal cell apoptosis (TUNEL assay).

RESULTSThe rats in the two putrescine- treated groups showed mild edema in some renal tissues without obvious necrosis. In P1 and P2 groups, serum Cr and BUN levels differed significantly at each time point of measurement (P<0.01 and P<0.05, respectively), and were significantly higher than the levels in the control group (P<0.01 and P<0.05, respectively). The two putrescine-treated groups showed gradually increased renal cell apoptosis with time, reaching the peak levels at 96 h and 48 h, respectively. The peak renal cell apoptosis rates in P1 [(24.78∓2.19)%] and P2 [(26.27∓2.13)%] group were significantly higher than the rate in the control group [(4.47∓0.33)%, P<0.01].

CONCLUSIONExogenous putrescine can lead to renal function impairment and induce renal cell apoptosis in rats, and the severity of these changes appeared to be associated with the blood concentration of exogenous putrescine.

Animals ; Apoptosis ; drug effects ; Kidney ; drug effects ; physiopathology ; Putrescine ; adverse effects ; blood ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the effect of the decomposition products of necrotic tissues from wounds on the serum levels of inflammation factors in comparison with endotoxin.

METHODSThirty adult New Zealand rabbits were randomly divided into 3 groups and received injections of saline, necrotic tissue homogenate or endotoxin. From each rabbit, blood samples (2 ml) were collected from the central artery of the ears at 0, 2, 6, 12, 24, 30, 36, 48, and 60 h after the injection for measurement of serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1) and IL-6.

RESULTSThe serum level of TNF-α, IL-1 and IL-6 in the rabbits increased 2-4 h after injection of the necrotic tissue homogenate and reached the peak level at 12 h, followed by a gradual reduction since 36 h. No obvious changes in the levels of the inflammatory factors were found in saline group (P<0.01). Compared with endotoxin, necrotic tissue homogenate resulted in an early increment (2-4 h vs 5-6 h) and significantly higher peak levels (at 30 h) of the inflammation factors (P<0.05). Curve fitting showed a distinct difference between necrotic tissue homogenate and endotoxin in their effect on the inflammatory factors.

CONCLUSIONThe necrotic tissue decomposition products contain toxic substances that possess a different toxicity profile from endotoxin, and their toxicity can be even stronger.

Animals ; Endotoxins ; adverse effects ; Inflammation ; Interleukin-1 ; blood ; Interleukin-6 ; blood ; Necrosis ; Rabbits ; Tumor Necrosis Factor-alpha ; blood ; Wounds and Injuries ; blood ; pathology